What is the Cap X Meaning in this Formula

[Marcus House]

Hello I came across a CoC formula and was wondering if anyone in the community could answer this question. The formula is:

CoC=(NOI - Debt Service - Cap X)/(Acquisition Cost)

What is the Cap X? There is the monthly amount that you have to put away every month towards future Capital project like roofing etc, then there is the amount of money that is needed for the capital improvement that will be made to the multifamily property immediately after closing prior to raising rent (typically we include this as part of our capital raise). Trying to figure out which is being referred to in this formula. 

[Allan C.]

@Brock Mogensen while capex items are one off, you should include amortized capex in your return estimates so that you have a better portrayal of Long term returns. Simply divide the capital expenditure by service life.